Chronic P. aeruginosa infection is associated with increased morbidity and mortality in patients with cystic fibrosis (CF). Current understanding of risk factors for acquisition is limited and so the aim of this study was to examine a large sample of environmental waters from diverse sources. Environmental water samples [n= 7904] from jacuzzis, hydrants, swimming pools, hot tubs, plunge pools, bottled natural mineral water (NMW), taps, springs, ice machines, water coolers, bores and showers were examined for the presence of P...

To identify microbial squalene that has been widely used in various industrial applications, intracellular formation of photosynthetic squalene was investigated using the previously engineered Synechococcus elongatus PCC 7942 strain. Unlike the proposed localization of squalene in the membrane bilayer, small droplets were identified in the cytoplasm of S. elongatus PCC 7942 as squalene using transmission electron microscopy analysis. Determination of the diameters of the squalene droplets with manual examination of 1,016 droplets in different squalene-producing strains indicated larger squalene droplets in larger cells...

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a worldwide concern. Cattle are their main reservoir and may contaminate watercourses through manure. We characterized a collection of 38 STEC O157:H7 strains isolated from surface water in feedlots areas (puddles inside pens formed after the rainfall or by spill around drinking troughs, and small water courses and lagoons, formed by runoff). Nineteen (50.0%) strains harbored stx2a /stx2c genes, 18 (47.4%) stx2c and one stx1a /stx2c . All strains harbored eae, ehxA, rfbO157 , and fliCH 7 genes, and the putative virulence determinants ECSP_0242, ECSP_2687 and ECSP_3620...

The aim of the present work was to evaluate the ability of the native yeast Rhodosporidium fluviale to control Botrytis cinerea on apple fruit and to study the possible mechanisms of action with the goal of improving the control of gray mold. For this, the influence of application time of the yeast was studied simulating preventive and curative effects. Also, the effect of nonviable cells of the yeast in the biocontrol was assessed. According to the results obtained, the following mechanisms of action of Rhodosporidium fluviale could be proposed: 1-competition for space, 2- direct interaction between antagonist and pathogen, 3- induction of β-1,3-glucanase in apple tissue, 4- Probable production of glucanase in the apple wounds and 5- antifungal action of cellular components, probably chitin, present in the wall of yeast cells that could be the explanation for the activity of nonviable cells...

Fresh-cut produce is at greater risk of Salmonella contamination. Detection and early warning systems play an important role in reducing the dissemination of contaminated products. One-step Reverse Transcription Polymerase Chain Reaction (RT-qPCR) targeting Salmonella tmRNA with or without a 6-h enrichment was evaluated for the detection of Salmonella in fresh-cut vegetables after 6-h storage. LOD of one-step RT-qPCR was 1.0 CFU ml-1 (about 100 copies tmRNA ml-1 ) by assessed 10-fold serially diluted RNA from 106 CFU ml-1 bacteria culture...

In honeys, several molecules have been known for their antibacterial or wound healing properties. Corsican honeys just began to be tested for their antimicrobial activity with promising results on Pseudomonas aeruginosa. So, identification of active molecules and their mode of action was determined. Hydrogen peroxide concentrations were evaluated and, in parallel, the minimal inhibitory concentrations (MIC) values were performed with and without catalase. More, the quantity of phenolic compounds and ORAC assay were measured...

Heat stable antifungal factor (HSAF) is considered to be a potential biological pesticide due to its broad antifungal activity and novel mode of action. However, few studies have reported on HSAF production during fermentation. Thus, this work was executed to optimize the medium composition to maximize HSAF production by Lysobacter enzymogenes OH11, with soybean flour, glucose, and CaCl2 identified as suitable nutrients with concentrations of 8.00, 7.89, and 0.72 g L-1 , respectively. Simultaneously, the quantitative analysis of HSAF production was established by eliminating the emulsification problem, and the highest HSAF production was determined to be 356...

Fusarium head blight (FHB) caused by Fusarium graminearum species complex is a devastating disease that causes extensive yield and quality losses to wheat around the world. Fungicide application and breeding for resistance are among the most important tools to counteract FHB. Biological control is an additional tool that can be used as part of an integrated management of FHB. Bacillus velezensis RC 218, Brevibacillus sp. RC 263 and Streptomyces sp. RC 87B were selected by their potential to control FHB and deoxynivalenol production...

Bacterial wilt of Curcuma alismatifolia (Patumma) caused by Ralstonia solanacearum is a major disease affecting the quality of rhizome exports. Traditionally, R. solanacearum is classified into five races based on differences in host range and six biovars based on biochemical properties. Recently a classification scheme based on phylotypes and sequevars was presented by the scientific community as a tool for determining phylogenetic relationships within R. solanacearum. This study used traditional and molecular methods to identify R...

Trans-4-Hydroxy-L-proline (trans-Hyp) is a valuable chiral building block for the synthesis of pharmaceutical intermediates. Bioconversion of L-proline using recombinant strain with proline-4-hydroxylase (P4H) is a preferred biocatalytic process in the economical production of trans-Hyp. In the present study, a recombinant E. coli overexpressing hydroxylase (P4H), γ-glutamyl kinase and glutamate-semialdehyde dehydrogenase (ProBA) genes were constructed by knocking out the key genes in the metabolism. These key genes contained putA encoding proline dehydrogenase (PutA) in the L-proline metabolism and other catalytic enzyme genes, sucAB encoding α-ketoglutarate dehydrogenase (SucAB), aceAK encoding isocitratelyase (AceA) and isocitrate dehydrogenase kinase/phosphatase (AceK) in the TCA cycle...

A novel κ-carrageenase gene (CgkB) has been cloned from Pedobacter hainanensis NJ-02 and expressed heterologously in Escherichia coliBL21 (DE3). It consisted of 1935 bp and encoded 644 amino acid residues with a molecular weight of 71.61 kDa. The recombinant enzyme showed maximal activity of 2458 U mg-1 at 40°C and pH 8.0. Additionally, it could retain more than 70% of its maximal activity after being incubated at pH of 5.5-10.0 below 40°C. K+ and a broad range of NaCl can activate the enzyme. The Km and Vmax of CgkB was 2...

The effectiveness of several cationic disinfectants as well as colistin and polymyxin B were assessed under different growth conditions against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa strains. These conditions included different media (MH1, MH2, TSB and LB) and plate material (polypropylene and polystyrene). Results showed that MIC/MBC values of colistin and polymyxin B were significantly lower on polypropylene plates when compared to polystyrene plates regardless of media used. There were also differences for MIC/MBC values to certain biocides e...

Magnetotactic bacteria (MTB) have the unique ability to produce magnetic particles surrounded by a biomembrane to form the magnetosome organelle. Therefore, MTB have novel physical and magnetic properties and have consequently been used in several biotechnological applications. The magnetic properties of these microorganisms and their magnetosomes have, however, never been used for the generation of electricity as described in this letter. Comparisons were made between, firstly, the electricity generated from purified magnetosomes, MTB culture (bacterial cells with magnetosomes) and sterile, liquid growth medium (control)...

Inteins (Internal proteins) are self-splicing transportable genetic elements present in conserved regions of housekeeping genes. The study highlights the importance of intein as a potential diagnostic marker for species-specific identification of Candida tropicalis, a rapidly emerging opportunistic human pathogen. Initial steps of primer validation, sequence alignment, phylogenetic tree analysis, gel electrophoresis and Real-Time PCR assays were performed to confirm the specificity of the designed primers. The primers were selective for C...

The genus Photobacterium comprises species of marine bacteria, commonly found in open-ocean and deep-sea environments. Some species (e.g. Photobacterium phosphoreum) are associated with fish spoilage. Recently, culture-independent studies have drawn attention to the presence of photobacteria on meat. This study employed a comparative isolation approach of Photobacterium spp. and aimed to develop an adapted isolation procedure for recovery from food samples, as demonstrated for different meats: Marine broth is used for resuspending and dilution of food samples, and cultivation on marine broth agar supplemented with meat extract and vancomycin at 15 °C for 72 hours...

Salmonella pathogenicity relies on virulence factors many of which are clustered within the Salmonella pathogenicity islands (SPIs). Salmonella also harbors mobile genetic elements such as virulence plasmids, prophage-like elements and antimicrobial resistance genes which can contribute to increase its pathogenicity. Here, we have genetically characterized a selected S. Typhimurium strain (CCRJ_26) from our previous study with Multiple Drugs Resistant profile and high-frequency PFGE clonal profile which apparently persists in the pork production center of Rio de Janeiro State, Brazil...